Management Of Glaucoma In Developing Countries: Challenges And Opportunities For Improvement.

Glaucoma is the leading cause of blindness in the developed and developing world. Not only is the clinical impact of this disease considerable, but associated economic and humanistic burdens - affecting patients, caregivers, and society - are substantial. Since glaucoma is an age-related disorder and populations in many developing countries are aging at a faster pace than in the developed world, increasing attention is being focused on ways to ameliorate the burdens of illness. In this paper, we examine the burdens of glaucoma with particular focus on developing countries, discuss some of the challenges that exist in delivering optimal glaucoma management within budget constraints, and bring into perspective how we could improve current healthcare systems, leverage technology, and strike an appropriate balance between cost and quality of care, thereby offering considerations to payors and policymakers in these countries that may result in longer-term cost savings, while concurrently striving to achieve the WHO Vision on the prevention of blindness and visual impairment.

Transpalpebral Electrical Stimulation as a Novel Therapeutic Approach to Decrease Intraocular Pressure for Open-Angle Glaucoma: A Pilot Study.

PURPOSE: To determine the effect on intraocular pressure of transpalpebral specific exogenous voltages in a cohort of open-angle glaucoma patients. METHODS: This is a prospective, comparative, and experimental pilot study. The electrical stimuli applied consisted of 10 Hz, biphasic, nonrectangular current pulses (100 µA) delivered from an isolated constant current stimulator. At intake, baseline IOP measurements were obtained from each eye. The measurement was repeated before and after microstimulation until the end of the treatment. RESULTS: Seventy-eight eyes of 46 patients diagnosed with POAG were studied: 58 eyes with maximum tolerated medical treatment and 20 eyes without treatment (naïve). The mean baseline IOP on the treated POAG group was 19.25 mmHg ± 4.71. Baseline IOP on the naïve group was 20.38 mmHg ± 3.28. At the four-month follow-up visit, the mean IOP value on the treatment group was 14.41 mmHg ± 2.06 (P < 0.0001). The obtained mean IOP measurement on the treatment-naïve group was 15.29 mmHg ± 2.28 (P < 0.0001). CONCLUSIONS: The hypotensive response obtained using transpalpebral electrical stimulation on POAG patients, both on treatment-naïve patients and on patients receiving maximum tolerable treatment, was statistically significant when comparing basal IOP measurements to those obtained at the four-month follow-up visit.

Effects of topical travoprost 0.004% on intraocular pressure and corneal biomechanical properties in an animal model.

PURPOSE: To determine whether topical application of travoprost 0.004% induces changes in corneal biomechanical properties affecting intraocular pressure (IOP) values in rabbits. METHODS: Both eyes of 10 New Zealand rabbits were measured 3 times with the Ocular Response Analyzer (ORA) before treatment. Each measurement included corneal hysteresis (CH), corneal resistance factor (CRF), corneal-corrected IOP (IOPcc), and Goldmann equivalent IOP (IOPg). A drop of travoprost 0.004% was applied once daily in right eyes for 3 months; left eyes received no treatments. After 3 months of treatment both eyes of all rabbits were again measured 3 times. After complete keratectomy of both eyes, tissues prepared with hematoxylin-eosin stain were analyzed by means of light microscopy. RESULTS: The mean pre- and post-treatment IOPg, respectively, for right eyes was 9.92 ± 5.64 mm Hg and 7.62 ± 2.99 mm Hg (P = 0.027); IOPcc, 19.81 ± 5.25 mm Hg and 17.79 ± 4.09 mm Hg (P = 0.063); CRF, 1.65 ± 1.63 mm Hg and 2.18 ± 2.50 mm Hg (P = 0.266); and CH, 2.79 ± 1.74 mm Hg and 2.64 ± 2.08 mm Hg (P = 0.72). Mean post-treatment right and left eye IOPg values were, respectively, 7.62 ± 2.99 and 10.30 ± 4.40 (P = 0.002); IOPcc, 17.79 ± 4.09 mm Hg and 20.37 ± 4.32 mm Hg (P = 0.009); CRF, 1.65 ± 1.63 mm Hg and 2.17 ± 2.47 mm Hg (P = 0.274); and CH, 2.79 ± 1.74 mm Hg and 2.54 ± 2.08 mm Hg (P = 0.575). No difference in CH and CRF was observed between treated and untreated eyes. CONCLUSIONS: Post-treatment reduction of IOP in treated eyes was a direct hypotensive effect of travoprost 0.004% and was not affected by changes in corneal biomechanical properties (CH and CRF), resulting in real lower IOP values.

Intraocular pressure control after the implantation of a second Ahmed glaucoma valve.

The objective of this study is to evaluate the efficacy and safety of a second Ahmed glaucoma valve (AGV) in eyes with refractory glaucoma that had undergone prior Ahmed device implantation. This multicenter, retrospective study evaluated 58 eyes (58 patients) that underwent a second AGV (model S2-n = 50, model FP7-n = 8) due to uncontrolled IOP under maximal medical therapy. Outcome measures included IOP, visual acuity, number of glaucoma medications, and postoperative complications. Success was defined as IOP <21 mmHg (criterion 1) or 30 % reduction of IOP (criterion 2) with or without hypotensive medications. Persistent hypotony (IOP <5 mmHg after 3 months of follow-up), loss of light perception, and reintervention for IOP control were defined as failure. Mean preoperative IOP and mean IOPs at 12 and 30 months were 27.55 ± 1.16 mmHg (n = 58), 14.45 ± 0.83 mmHg (n = 42), and 14.81 ± 0.87 mmHg (n = 16), respectively. The mean numbers of glaucoma medications preoperatively at 12 and 30 months were 3.17 ± 0.16 (n = 58), 1.81 ± 0.2 (n = 42), and 1.83 ± 0.35 (n = 18), respectively. The reductions in mean IOP and number of medications were statistically significant at all time intervals (P < 0.001). According to criterion 1, Kaplan-Meier survival curves disclosed success rates of 62.9 % at 12 months and 56.6 % at 30 months. According to criterion 2, Kaplan-Meier survival curves disclosed success rates of 43.9 % at 12 months and 32.9 % at 30 months. The most frequent early complication was hypertensive phase (10.3 %) and the most frequent late complication was corneal edema (17.2 %). Second AGV implantation may effectively reduce IOP in eyes with uncontrolled glaucoma, and is associated with relatively few complications.

Achieving Target Pressures with Combined Surgery: Primary Patchless Ahmed Valve Combined with Phacoemulsification vs Primary Phacotrabeculectomy.

PURPOSE: To evaluate the ability of phacoemulsification combined with either primary trabeculectomy (PT) or primary Ahmed glaucoma valve implantation (PAVI) to achieve target intraocular pressures (TIOP) in adults with primary open angle glaucoma. MATERIALS AND METHODS: Chart review of 214 adult patients operated between January 2002 and June 2008 with a minimum follow-up of 6 months. Group 1 comprised 181 eyes of 166 patients undergoing PT while group 2 included 50 eyes of 49 patients in combination with primary AVI. Target lOPs were pre-determined for each patient and success was defined as an IOP at or lower than target with or without medications. An IOP above target, loss of light perception or need for additional procedures to lower IOP were considered a failure. RESULTS: Mean preoperative IOP was 17.2 mm Hg in group 1 and 17.3 in group 2. Mean postoperative IOPs were 10.2 and 9.2 on day 1, 12.2 and 11.6 at year 1, and 10.7 in both groups at year 5. Survival rates in groups 1 and 2 were 96.7 vs 96% at 6 months, 89 vs 96% at 12 months, 83.5 vs 96% at 24 months and 79.4 vs 89.1% at 36, 48 and 72 months. Transient bleb leaks were more frequent in group 1 (26 eyes, 14.4 vs 0%, p = 0.001) and transient choroidal detachments were more frequent in group 2 (7 eyes, 3.9 vs 6 eyes, 12%, p = 0.038). CONCLUSION: Midterm results for achieving target pressures using combined phacoemulsification with either PT or PAVI are comparable. The profile of complications is different for the two procedures. How to cite this article: Albis-Donado O, Sánchez-Noguera CC, Cárdenas-Gómez L, Castañeda-Diez R, Thomas R, Gil-Carrasco F. Achieving Target Pressures with Combined Surgery: Primary Patchless Ahmed Valve Combined with Phacoemulsification vs Primary Phacotrabeculectomy. J Curr Glaucoma Pract 2015;9(1):6-11.

[Effect of cryotherapy over the expression of vascular endothelial growth factor and pigment epithelium-derived factor]. / Efecto de la crioterapia en la regulación de la expresión del factor de crecimiento del endotelio vascular y del factor derivado del epitelio pigmentado.

BACKGROUND: Cryotherapy is a no invasive technique that uses intense cold to freeze and destroy cancer tissues. There are no descriptions of its effects over the expression of vascular endothelial growth factor and pigment epithelium-derived factor. METHODS: Experimental study in cryogenic spot were applied in the right sclera of twelve pigs for ten minutes. Other 3 pigs were used as normal controls. Animals were sacrificed at 7, 14 and 21 and the tissues of choriodes and retina were dissected in areas of approximately 1 cm2 surrounding cryogenic spots. Expression levels of vascular endothelial growth factor and pigment epithelium-derived factor were determined analyzed using polymerase chain reaction coupled to reverse-transcription. RESULTS: Vascular endothelial growth factor was significantly downregulated (24%, p< 0.05) seven days post-treatment meanwhile pigment epithelium-derived factor levels increased 44.8% (p< 0.05) as compared to normal controls (untreated). Both vascular endothelial growth factor and pigment epithelium-derived factor levels remain the same until day 14 but returned to basal expression at day 21. DISCUSSION: This work expose the relation of cryotherapy with the expression of two factors related to angiogenesis. RESULTS showed significant changes on the expression of vascular endothelial growth factor and pigment epithelium-derived factor illustrating that both proteins are regulated in response to cryogenic treatment in relatively short periods (21 days).

Antecedentes: la crioterapia es una técnica no invasiva que usa frio intenso para congelar y destruir los tejidos cancerosos. Sus efectos en la expresión del factor de crecimiento del endotelio vascular y el factor derivado del epitelio pigmentado no se han descrito. Material y métodos: estudio experimental en modelos experimentales de crioterapia. En la esclera del ojo derecho de 12 cerdos se aplicó un punto de congelamiento durante 10 segundos. Se usaron 3 cerdos como controles normales. Los animales se sacrificaron a los 7, 14 y 21 días y el tejido de coroides y retina se seccionó en áreas de aproximadamente 1 cm2 circundantes al punto de congelamiento. Los niveles de expresión del factor de crecimiento del endotelio vascular y factor derivado del epitelio pigmentado se determinaron y analizaron por reacción en cadena de la polimerasa acoplada a reverso-transcripción. Resultados: los niveles de factor de crecimiento del endotelio vascular disminuyeron significativamente (24%, p < 0.05) a los 7 días postratamiento, mientras que la expresión del factor derivado del epitelio pigmentado aumentó 44.8% (p< 0.05) en comparación con los niveles de las muestras normales. Los niveles de expresión se mantuvieron hasta el día 14 y regresaron a valores basales en el día 21. Conclusiones: este trabajo expone la relación entre la crioterapia y la expresión de dos factores angiogénicos. Los resultados muestran cambios significativos en la expresión del factor de crecimiento del endotelio vascular y factor derivado del epitelio pigmentado, y evidencian que ambas proteínas son reguladas en respuesta al tratamiento criogénico en periodos relativamente cortos (21 días).

Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

Adjunctive bevacizumab in patients undergoing Ahmed valve implantation: a pilot study.

BACKGROUND AND OBJECTIVE: To report on preliminary findings of adjunctive subconjunctival bevacizumab (SCB) injections in patients undergoing Ahmed valve implantation (AVI) (New World Medical, Rancho Cucamonga, CA). PATIENTS AND METHODS: The study was approved by the institution's ethics committee. Patients were prospectively recruited during a 1-month period and randomized to receive AVI with postoperative SCB (days 1 and 7, n = 7) or AVI without SCB (n = 6). RESULTS: Baseline intraocular pressure (IOP) in the treatment (AVI+SCB) group was 19.4 ± 8.6 mm Hg, whereas baseline IOP in the control (AVI) group was 32.1 ± 17.7 mm Hg (P = .119). Final IOP was 13.8 mm Hg (n = 7) for the treatment group and 12.7 mm Hg for the control group (n = 5, P = .790). One eye in the control group required further glaucoma intervention at day 45 and was considered a failure. The pre-massage postoperative IOP was significantly lower for the treatment group only at day 45 (16.1 vs 26.0 mm Hg, P = .012). Mean post-massage IOP was significantly lower in the treatment group at day 15 (11.28 vs 17.16 mm Hg, P = .004), day 30 (11.28 vs 20.83 mm Hg, P = .015), and day 45 (12.16 vs 21.33 mm Hg, P = .001), and similar at month 3. Mean change in bleb area was 11.4 mm(2) in the treatment group and -0.4 mm(2) in the control group (P = .036 and P = .361, respectively, Student's paired samples t test). CONCLUSION: Bevacizumab was associated with a less aggressive hypertensive period as measured by post-massage IOP measurements, postoperative glaucoma medications, and cross-sectional bleb area by ultrasound. Further prospective studies are needed to better understand the utility of SCB at the time of AVI surgery.

Patterned laser trabeculoplasty.

BACKGROUND AND OBJECTIVE: A novel computer-guided laser treatment for open-angle glaucoma, called patterned laser trabeculoplasty, and its preliminary clinical evaluation is described. PATIENTS AND METHODS: Forty-seven eyes of 25 patients with open-angle glaucoma received 532-nm laser treatment with 100-µm spots. Power was titrated for trabecular meshwork blanching at 10 ms and sub-visible treatment was applied with 5-ms pulses. The arc patterns of 66 spots rotated automatically after each laser application so that the new pattern was applied at an untreated position. RESULTS: Approximately 1,100 laser spots were placed per eye in 16 steps, covering 360° of trabecular meshwork. The intraocular pressure decreased from the pretreatment level of 21.9 ± 4.1 to 16.0 ± 2.3 mm Hg at 1 month (n = 41) and remained stable around 15.5 ± 2.7 mm Hg during 6 months of follow-up (n = 30). CONCLUSION: Patterned laser trabeculoplasty provides rapid, precise, and minimally traumatic (sub-visible) computer-guided treatment with exact abutment of the patterns, exhibiting a 24% reduction in intraocular pressure during 6 months of follow-up (P < .01).

Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma.

PURPOSE: To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children. MATERIALS AND METHODS: A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications. RESULTS: Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries. CONCLUSION: Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique.

The efficacy and safety of two fixed combinations: timolol-dorzolamide-brimonidine versus timolol-dorzolamide. A prospective, randomized, double-masked, multi-center, 6-month clinical trial.

We compared the efficacy and safety of a new fixed combination of timolol 0.5%/odorzolamide 20%/brimonidine 0.2% in ophthalmic solution versus a fixed combination of timolol 0.5%/dorzolamide 2% in patients with open-angle glaucoma or ocular hypertension. The fixed triple combination was significantly more efficient in mean intraocular pressure reduction from baseline throughout the six-month follow-up.

Measurement of retinal nerve fiber layer thickness in normal and glaucomatous Cocker Spaniels by scanning laser polarimetry.

OBJECTIVE: To measure changes in the thickness of the retinal nerve fiber layer in normal and early glaucomatous dogs with scanning laser polarimetry. ANIMALS STUDIED: A total of 45 eyes, 32 normal and 13 glaucomatous eyes, of American Cocker Spaniels with primary glaucoma were used. All eyes were evaluated through a complete neuro-ophthalmic examination, tonometry, gonioscopy, slit-lamp biomicroscopy, and indirect ophthalmoscopy prior to enucleation. METHODS: The retinal nerve fiber layer thickness was measured in anesthetized animals with scanning laser polarimetry (Nerve fiber analyzer, GDx; Laser Diagnostic Technologies, LTD, San Diego, CA, USA). Glaucomatous eyes retained some vision at the time of this study. RESULTS: The mean +/- SD of the retinal nerve fiber layer thickness was 141.69 +/- 18 microm for normal dogs and 105.08 +/- 23.86 microm for visual glaucomatous dogs. The average retinal nerve fiber layer thickness in the superior and inferior retinal quadrants was 148.03 +/- 8.5 and 141.06 +/- 8.73 microm, respectively, for normal dogs, and 106.61 +/- 25.77 and 107.08 +/- 24.99 microm in the superior and inferior retinal quadrants, respectively, for glaucomatous dogs. The superior to nasal retinal nerve fiber layer thickness ratio was 1.45 for normal dogs and 1.26 for visual glaucomatous dogs. CONCLUSIONS: Using scanning laser polarimetry it was possible to detect changes in retinal nerve fiber layer thickness in glaucomatous dogs at early stages of the disease. Therefore, this instrument has the potential to improve the clinical management of canine glaucoma by detecting progressive changes to the retinal nerve fiber layer.

Inducción de cambio en el patrón topográfico en la cirugía filtrante de glaucoma / Induced changes in topographic pattern after filterin glaucoma surgery

Conocer el cambio inducido y poder refractivo en la superficie anterior y posterior de la córnea en pacientes operados de cirugía filtrante de glaucoma. Estudio prospectivo, longitudinal, experimental y comparativo. Se escogieron aleatoriamente 33 ojos sometidos a trabeculectomías y colocación de valvulas de Ahmed. Se valoraron con el sistema Orbscan II, (Bausch & Lomb Surgical, Inc. (USA) los patrones de elevación de la superficie anterior, posterior y determinación, comparación de astigmatismos inducidos en el preoperatorio y postoperatorio (primer, tercer y sexto mes); se aplicaron pruebas no paramétricas de Friedman y de Mann-Whitney. Todos los pacientes incluidos no tenían cirugías oculares previas ni combinadas para el momento del estudio. 33 ojos de 33 pacientes, 21 ojos operados (63,6 por ciento) con trabeculectomía y 12 ojos (36.4 por ciento) con válvula de Ahmed. La edad promedio era de 64.29 ± 4.77 (trabeculectomía) y de 50 ± 26.50 operados con válvula de Ahmed (IVA). Al comparar los cambios en la superficie posterior entre los grupos se observó en el preoperatorio una p de 0.864 y en el postoperatorio de 0.011 (primer mes), 0.061 (tercer mes) y de 0.007 (sexto mes), mostrando una diferencia asintótica (bilateral). Los cambios pueden deberse no solamente a la técnica quirúrgica sino también a la presión intraocular, cicatrización, poder queratométrico, a la experiencia quirúrgica del cirujano, entre otros factores.

Pars plana vitrectomy and lamina cribrosa puncture in absolute glaucoma.

Two patients with refractory end-stage glaucoma who had no light perception underwent pars plana vitrectomy and lamina cribrosa puncture to relieve pain and decrease intraocular pressure. The patients presented with blind, painful eyes and high intraocular pressure (> 40 mm Hg). After the procedure, the pain was relieved and the intraocular pressure was lowered in both cases. The patients remained asymptomatic. Pars plana vitrectomy and lamina cribrosa puncture might be related to the decrease of intraocular pressure, probably by facilitating drainage of aqueous humor through the optic nerve.

Experiencia clínica inicial con la válvula de Ahmed en pacientes / Initial clinical experience with the ahmed valve in patients with angle-recession glaucoma

Objetivo: Evaluar la utilidad de la válvula de Ahmed en pacientes con glaucoma secundario a recesión angular. Método: Estudio retrospectivo en el que se evaluaron 12 pacientes (12 ojos) con edad promedio de 40.7 años, con un seguimiento promedio de 7.3 meses [7.9 (2-30 meses)]. Resultados: En 66.6 por ciento de los casos (8 ojos) se logró un control tensional exitoso. La presión intraocular (PIO) disminuyó de 32.5 ñ10.2 mmHg (22-54 mmHg) con 3.1 ñ0.7 medicamentos antiglaucomatosos en el preoperatorio, a 19 ñ5.4 mmHg (12-30 mmHg) (p<0.05) con 0 medicamentos (p<0.05) en el último día de seguimiento. La complicación más frecuente fue el enquistamiento de la vesícula (33.3 por ciento). Conclusión: La colocación de la válvula de Ahmed en pacientes con glaucoma secundario a recesión angular constituye una opción terapéutica más que produce un control tensional similar a lo observado con otro tipo de implantes.

Implante de válvula de ahmed en pacientes con glaucoma congénito / Ahmed implant in subjects with congenital glaucoma

Se realizó una revisión retrospectiva de un total de 27 expedientes de pacientes con diagnóstico de glaucoma congénito los cuales fueron sometidos a implante primario de válvula de Ahmed, en su mayoría sometidos a varias intervenciones quirúrgicas o con tratamiento antiglaucoma en un periodo comprendido entre los años de 1994 a 1998 en el Servicio de Glaucoma de la Asociación Para Evitar la Ceguera en México. El número total de ojos registrados fue de 32 de los cuales fueron eliminados 5 por tratarse de ojos contralaterales y 9 rechazados por no cumplir con alguno de los criterios de inclusión. El número total de ojos analizados en este trabajo es de 18; once izquierdos y siete derechos. La edad media de los pacientes fue de 8 años. El número de cirugías previas por caso fue en promedio de 3.1 cirugías. El número de medicamentos antiglaucomatosos utilizados previos a la cirugía por caso fue en promedio 2.33. El tiempo promedio de seguimientos en meses fue de 21.5 meses con un periodo mínimo de seguimiento de 6 meses y máximo de 48 meses. Quince pacientes (83.3 por ciento) habían sido sometidos previamente a alguna cirugía para el tratamiento de glaucoma de estos 14 tenían al menos 2 cirugías previas. El uso de medicamentos antiglaucomatosos fue positivo en 66.6 por ciento de los pacientes estudiados.El número total de complicaciones fue de 8 casos siendo la complicación más común el desprendimiento coroideo seroso en 6 casos y la mala posición del tubo valvular en 2 casos; de dichas complicaciones, 7 fueron resueltas con tratamiento médico o quirúrgico según el caso. De acuerdo a los criterios de éxito los resultados fueron: éxito completo en 4 casos (22.2 por ciento), éxito calificado 8 casos (44.4 por ciento), falla calificada en 4 casos (22.2 por ciento) y falla completa en 2 casos (1l.1 por ciento). El porcentaje de éxito para esta serie fue de 66.6 por ciento y el de fracaso de 33.4 por ciento.